get-thread

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden. It discloses that results are returned oldest-first, explains the threading algorithm (imap: id vs normalized subject), and lists the exact return fields (normalized subject, id, date, subject, sender, read state). No contradictions exist.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is four sentences, front-loaded with the use condition. Every sentence serves a purpose: usage, threading logic, return format, and when-not-to-use. No fluff or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given an output schema exists, the description adds extra value by detailing the return fields and behavior. It covers all necessary aspects: input requirements, threading behavior, output format, and exclusion cases. Complete for the tool's complexity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description does not add new information about the parameters beyond what the schema already provides; the only extra detail is the pattern hint for id, which is already captured in the schema's pattern. No elaboration on limit, account, or mailbox beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb-resource ('get-thread') and clearly states the tool's purpose: take one message id and return the whole conversation. It distinguishes itself from siblings like get-message and search-messages by explaining the threading logic based on References/Message-ID vs normalized subject.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states when to use ('have one message id and want the whole conversation') and when not to use ('only need the single message' or 'searching by arbitrary criteria'), naming alternative tools (get-message, search-messages). This provides clear guidance for agent decision-making.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.